1. Field of the Invention
This invention relates to novel compounds useful for the treatment of psoriasis through topical application to improve and heal the skin lesions of psoriasis in humans.
2. Description of the Prior Art
Psoriasis is a chronic disease, and remains a disfiguring and disabling cutaneous impairment to millions of persons. Its etiology is completely unknown, and therefore, prevention remains inconceivable. Therapy has necessarily been empiric, and has included the systemic use of antimitotic drugs such as methotrexate to induce remissions of the lesions. However, acute and chronic toxicity on tissues other than skin has discredited use of methotrexate. Therefore, it is imperative that other means of therapy be found for external delivery of drugs so that toxicity is confined chiefly to the skin, or by the discovery of new drugs having nontoxic attributes.
U.S. Pat. No. 4,067,975 discloses the treatment of psoriasis with a family of 6-substituted nicotinamides, 6-substituted nicotinic acid and esters thereof and 2-substituted pyrazinamide or thionicotinamide. While such compounds have proven effective, their use must be accompanied by the application of Vitamin B.sub.3 to avoid possible hearing impairment in the patient.
U.S. Pat. No. 3,920,840 discloses the treatment of psoriasis with one of the degradation products of mechlorethamine hydrochloride, N-methyldiethanolamine, a compound which is not primarily either antimitotic nor allergic.